FR2525947A1 - METHOD AND DEVICE FOR FORMING PERFORATIONS IN BAR-SHAPED ARTICLES - Google Patents

Abstract

ACCORDING TO THE INVENTION, THE PROCESS AND THE DEVICE FOR FORMING PERFORATIONS 3 IN ARTICLES IN THE FORM OF BARS 5, IN WHICH EACH OF THE ARTICLES 5 IS MAINTAINED WHILE ITS MOVING IN A TRANSVERSAL DIRECTION WITH RESPECT TO ITS OWN AXIS ON A CONVEYOR 6, BY A RESPECTIVE MANEUVER 28, ARE SUCH AS EACH ARTICLE 5 IS DRIVEN IN ROTATION BY THIS MANEUVER 28 AROUND ITS AXIS IN SUCH KIND THAT IT RECEIVES, ALONG AT LEAST ONE CIRCUMFERENCE, A SUCCESSION OF PULSES LASER WHICH FORM EACH ONE OF THE RESPECTIVE PERFORATIONS 3. APPLICATION TO THE MANUFACTURE OF "LIGHT" CIGARETTES.

Description

The present invention relates to a process for the formation of

  perforations in shaped articles

  bars, using laser rays.

  The present invention finds a particularly advantageous application in the field of the production of smoking articles, in particular cigarettes, and the

  This memo will refer particularly to this application.

  without having to be considered as a limitation

of the generality of the invention.

  In the field of cigarette manufacture, it is known to manufacture so-called "light" or "light" cigarettes, that is to say cigarettes which have, in the region of the filter, several holes that allow the smoker to smoke. inhale, together with the smoke, a certain

  percentage of outside air, which shows the double advantage

  to dilute the inhaled smoke and reduce its temperature,

  and, consequently, to reduce the content of harmful elements.

  In the past, "light" cigarettes have been manufactured using needle devices

  efficiency has become increasingly limited with increasing

  production capacity of manufacturing machines

  In fact, when they are associated with machines for manufacturing cigarettes at relatively high production rates, said needle devices wear out after a relatively short period of use,

  which requires frequent interruptions in the production cycle

  tion. For the reasons explained above, said needle devices have recently been replaced, where possible, by laser beam perforating devices which have been made according to one of two different structural arrangements. two known structural arrangements and mentioned above, a pulsed laser beam is emitted by a fixed laser generator and directed on a cigarette to be pierced. The latter, during the piercing operation, is rolled between two surfaces facing such As a result, the holes drilled in the cigarette are distributed in a substantially uniform manner along at least one circumference. In the other of the two structural arrangements known and mentioned above, a high power laser generator is used to pierce each cigarette, it emits a single ray beam which is divided by fixed reflectors in several beams, in number equal to number of holes to drill In this case, the holes in each

  cigarette are made simultaneously without it being necessary

  to turn the cigarette around its axis.

  The two structural arrangements known and described above have significant disadvantages, which make them difficult to implement. In fact, the first structural arrangement requires that each cigarette

  is rolled between two surfaces opposite, and like the ciga-

  rette has, immediately before, already been "softened" or "lightened" following a first run made during the connection operations of a filter, a new rolling, in order to achieve the drilling, is particularly damaging to the extent o it certainly implies that the cigarette is partially emptied of its tobacco The second of the two structural arrangements known and described above is also difficult to implement for

  purely economic reasons, given the high

  and, consequently, the high cost of the laser generator

which must be used.

  The object of the present invention is to provide a method of forming perforations in bar-shaped articles, in particular cigarettes, which do not

  presents the disadvantages described above of the agencies

  structural elements known and presented above.

  This object is achieved by the present invention insofar as it relates to a method of forming

  perforations in bar-shaped articles, in particular

  particular of the following steps of driving said articles in displacement, transversely to their axis, along a predetermined advance path, by means of a conveyor on which said articles are spaced with constant spacing,

  to associate each of those articles with

  voyeur along at least part of said trajectory by means of a retaining device comprising, for each of said articles, a maneuvering member displaceable with said conveyor and mounted in rotation about its own axis, in order to communicate to the associated article, simultaneously with said displacement along said trajectory, a rotation about its axis, and using at least one laser generator block

  to form on each of those articles at least one

  punctures during rotation of the article around

of its axis.

  The present invention also relates to a device for implementing the method presented above, the device being characterized by the fact that it comprises a conveyor intended to drive said articles in displacement, transversely with respect to their axis, along a predetermined feed path, said conveyor being capable of supporting said articles with constant spacing, a retainer for coupling each of said articles to said conveyor along at least a portion of said path, said retainer comprising, for each of the said articles, an organ of

  movable with said conveyor and rotatably mounted

  tion about said axis, in order to communicate to the associated article, simultaneously with said displacement along said path, a rotation about its axis, and

  at least one laser generator block

  to form, in each of said articles, at least one ring of perforations during said rotation

of the article around its axis.

  Other features and benefits of the

  present invention will flow from the description which follows,

  FIG. 1 schematically represents, in axial section, an exemplary embodiment of the device for perforating cigarettes according to the present invention;

  FIG. 2 is a section along line II-

  II of FIG. 1, in which the said perforation device

  ration is shown connected to input and output members of a machine to mount a filter on cigarettes and Figure 3 schematically shows a front view, partly in section, of a detail of the device of

Figures 1 and 2.

  In FIG. 1, the reference 1 designates in a general manner the device intended for the formation of two crowns 2 of perforation 3 in the outer envelope

  of cigarette filters 4 advancing with a speed sensitive

  constant along a circular path by means of a conveyor 6 This comprises a roller 7 whose interior is hollow and cylindrical, which is provided on its outer surface 8 (Figure 2) with several seats 9 arranged with a constant spacing P any of the

  other and parallel to the axis of the roll 7.

  As shown in FIG. 1, the roller 7 is provided with an inner annular end flange 10, the inner periphery of which is rigidly connected to the outer periphery of an annular end flange 11 of a coaxial tubular shaft 12 The shaft 12 passes through the roller 7 and supports, at its end opposite to that connected to the roller 7, a toothed wheel 13 coupled in a manner not shown to a source of motion, not shown. Shaft 12 passes through a hole 14 in a fixed wall of a filter-mounting machine generally designated by the outer surface of the wall being connected with a flange 17 of a tubular body 18 coaxial with the 12 to the outer surface of the flange 17 is connected, by means of several axial screws 19, only one of which is shown in FIG. ubular coaxial with the tubular body 18 and the shaft 12 is rotatably mounted in the two tubular bodies 18 and 20 by means of

  two bearings 21, the first of which is engaged in the

  of the body 18 and the second of which is inside the

body 20.

  The tubular body 20 has a cylindrical surface

  external drique 22 which is coupled in rotation, forming

  an airtight seal with a cylindrical surface between

  23 of the roll 7, and the tubular body 20 has a groove 24 disposed in a plane perpendicular to the axis of the shaft 12 and separated into two parts whose arrangement,

  around this axis will be described below.

  on one side, in a manner not shown, with a suction source, and on the other side, selectively, with a plurality of substantially radial holes extending inwardly from the bottom of each seat 9. An axial pin 26, aligned with said seat

  9 associated and serving as sliding guide prismati-

  that for an associated slider 27 extends for each seat 9 of the outer surface of the roller 7 opposite the wall 15 The slider 27 constitutes a part of a device

  maneuver 28 operating in such a way as to act on the cigar.

  rette 5 housed in the 9 associated seat in a way that will

  explained below, and this maneuvering device 28 con-

  other operating devices 28, a

  The restraining device generally designated by reference numeral 29. The retainer 29 further comprises two members

  curved guiding guides 30 extending out of the

  face 8 along an arc whose position and size will be

specified below.

  Each slide 27 comprises a tubular sleeve

  31 is slidably mounted and fixed in angular position on the associated pin 26 and carrying a radial pin on which is rotatably mounted a bearing 32 which can rotate in contact with the side walls of a groove 33 formed in the outer cylindrical surface 22 of the tubular body 20 and constituting therewith a drum cam 34 The groove 33 is formed such that during each rotation of the roll 7 it communicates about the axis of the shaft 12, a reciprocating movement each slider 27 between an advanced operating position, shown in the upper part of Figure 1, and a retracted position of rest, shown in the lower part of Figure 1 for this purpose, the groove 33 is formed of such so that it holds each slide in said operating position along an arc of displacement of this slide, the length of the arc being

defined below.

  From each sleeve 31, and to the outside

  In a direction opposite to the bearing 32, extends a projecting portion 35 traversed by a hole 36 coaxial with the associated seat 9 and in which a shaft 37 is rotatably mounted. This shaft 37 carries an elastic sleeve 38 connected to the end of the shaft facing said seat 9, the inner diameter of the sleeve 38 being such that it allows a slightly tight coupling between the sleeve 38 and an end of an associated cigarette 5 housed inside the associated seat 9 On the end of each shaft 37 which is opposed to that which carries the sleeve 38, a toothed wheel 39 is keyed and constitutes an end pinion or pinion.

  output of a gear train 40, the other pinion gear of which

  tremité or output, designated 41, is keyed on the shaft 12 The gear train 40 comprises a first gear 42 keyed on a shaft 43 rotatably mounted at its ends in the cylindrical bodies 18 and 20 and disposed at the inside a cavity 44 delimited between them On the shaft 43 is keyed a second toothed wheel which, with the aid of a toothed wheel 46 supported in a manner not shown in the cavity 44, is coupled to the toothing internal 47 of a cylindrical ring 48 coaxial with the shaft 12 and supported inside the tubular bodies 18 and 20 by bearings 49 A toothed wheel 50, which is also coaxial with the shaft 12 and which is coupled to the wheels teeth 39 of all shafts 37 is rigidly connected to the surface

outer ring 48.

  Inside the shaft 12 is rotatably mounted, with the aid of bearings 51, a tubular shaft 52, a first end of which is projecting from the shaft 12 to the third wheel adjacent to the wheel. toothed 13 and a toothed wheel 53 is keyed on the tubular shaft 52 and is coupled to a source of motion not shown, and the other end of the tubular shaft 52 is projecting from the end adjacent to the flange 11 of the shaft 12 and has an elongated axial slot 54 The shaft 52 can be traversed internally by a pulsed laser beam 55

  at a frequency and with a law of emission which will be

  below, which is emitted by a laser generator 55 disposed opposite the end of the shaft 52 which carries the toothed wheel 53 The beam 55 is deflected through the slot 54 towards the outside of the 52 with the aid of two reflectors 57 and 58 aligned along the axis of the shaft 52, and the reflector 57, on which the beam 55 falls first, is a semi-transparent mirror The mirror 57 divides the beam 55 in two beams 59 and 60, which are respectively focused by lenses 61 and 62 on filters

  4 so that they form the holes 3 of the crown 2.

  In operation, the cigarettes 5 are brought to the associated seats 9 of the roll 7 from a feed roll 63 which is substantially tangent to the roll 7 and which also has seats 64. Each of these when it reaches the point of tangency with the roller 7, releases the associated cigarette which engages in an associated seat 9 and is retained in the latter by suction it is so until each cigarette reaches an arc AB designated below by the terms of piercing arc, along which the cigarette is held within the associated seat 9 by the guide members Accordingly, said first portion of the groove 24 begins substantially in correspondence with said point of contact.

  tangency between rollers 7 and 63 and ends in corres-

  spawning with the beginning of the piercing arc AB in the direction of advancement of the cigarettes 5, while the other part of the groove 24 starts in correspondence with the end of the piercing arc AB and ends in correspondence with a point

  tangency between the roller 7 and an output roller 65.

  The latter discards cigarettes 5 seats 9 by aspirator-

  receiving them in respective axial seats 66.

  When cigarettes are transferred to

  roll 7 at said point of tangency of the latter with the roll

  the water 63, the sliders 27 are arranged in their rest position said retracted position, and are transferred by the effect of the inclination of the groove 33 of the cam 34 in their operating position said advanced position, substantially in correspondence with the In each case, each slider 27 is axially displaced so that the end of the associated cigarette engages in the associated sleeve 38, in correspondence with the end of the aspiration by the sliders. During its advance along the piercing arc AB, each slider 27 is held in a constant axial position by the groove 33 of the cam 34, which determines the

  disengaging each cigarette 5 from the sleeve 38 corres-

  laying during suction recovery through holes 25.

  The transmission ratio of the gear train is such that during the course of the piercing arc AB by each cigarette 5, the latter performs a rotation

  around its own axis by the effect of its accou-

  with the associated sleeve 38.

  In the example shown, the tubular shaft 52 is rotated with an angular velocity such that each complete rotation of the shaft 52 corresponds to an advance of the value of a spacing P of the cigarettes. the drilling arc AB is equal to a number N of spacing PN being the number of holes 3 of

each crown 2.

  With each rotation of the shaft 52, the generator 56 delivers a series of N laser pulses, which are emitted with a constant frequency during the time taken by the slot 54 to traverse the drilling arc AB. Consequently, with each rotation of the shaft 52, the generator 56 forms a hole in N cigarettes 5 successively distributed along the piercing arc AB Each cigarette 5 is therefore affected N times during its movement along the piercing arc AB and accordingly , at the exit of the cigarette, it has two rings 2 of N holes 3 which are uniformly distributed on the cigarette 5 because of the rotation of the latter about its axis by the effect of

  the coupling with the associated rotating sleeve 38.

  From the explanations given above, it follows that the angular velocity of the cigarettes 5 about their axis, because of their coupling with the associated sleeves 38, is inversely proportional to the length of the piercing arc AB As a consequence, by increasing the diameter of the roller 7, it is possible to increase the length of the drilling arc AB, for example to increase it until it is equal to 2 N spacings or spacings P In this case, the speed the rotation of the cigarettes 5 about their axis by the effect of their engagement in the sleeves 38 is reduced by half, while the rotational speed of the shaft 52 will have to be modified so that each complete rotation about its axis corresponds to an advance of the cigarettes 5 by the value of 2 spacings or spacings P Consequently, if the number of pulses emitted by

  the generator 56 remains constant and equal to n, at each rotation

  52 a cigarette 5 is touched twice, but each cigarette will always have two crowns

  2 of N holes 3 after having traversed the piercing arc AB.

  Naturally, the principle of the invention remaining the same, it is possible to introduce many modifications to the drilling device described above without departing from the scope of the present invention.

  For example, in a first variant of reali-

  However, the mirrors 57 and 58 may have a different orientation than the one described so that they can direct respective focused beams from the generators at any point within the space on the cigarettes. and unoriented along the axis of the shaft 52 In addition, more reflective mirrors can be used to form a corresponding number of crowns 2 of holes 3 or, if it is desired to reduce the length of the piercing arc, it is possible to form, at each pulse, several holes in different cigarettes, the latter result being obtainable in another variant embodiment, not shown, using

several laser generators.

  In another variant of embodiment not shown

  felt, which must be considered in isolation or in combination with the variants described above, may be provided sleeves combined with the sleeve 38 or replacing them,

  and in which cigarettes are engaged by their

  mity carrying the filter, with a law similar to that described

  Finally, in another variant of

  In the embodiment not shown, the roller 7 is arranged facing another roller 7 integral in rotation with the first and provided with similar slides 27 for the purpose of determining the feed of pairs of coaxial cigarettes connected to one another by a double filter which extends through the space defined between the two rollers 7, the pair of

  cigarettes being subjected to the effects of the laser generator 56.

  The latter will obviously be able to form two

  spaced pairs of crowns of holes on the double filter.

  Obviously, in all the variants men-

  above, the crowns 2 of holes 3 can be reduced to a single row of holes by removing one of the

mirrors 57 or 58.

he

Claims (12)

  1 Method of forming holes in articles   Bar-shaped keys, in particular cigarettes, characterized in that it comprises the following steps: driving said articles (5) in translation, transversely to their axes, along a path in advance determined by means of a conveyor (6)   wherein said articles (5) are spaced apart with a spacing   constant (P), coupling each of said articles (5) to said conveyor (6) along at least a portion of said   trajectory by means of a retaining device (29) comprising   nant, for each of said articles (5), an actuator (28) displaceable with said conveyor (6) and rotatably mounted about its own axis in order to communicate to the associated article (5), simultaneously with said translation the along said path, rotating about its axis, and using at least one laser generator block (56) to form on each of said articles (5) at least one ring (2) of perforation (3) during said rotation   of the article (5) around its axis.   2 Method according to claim 1, characterized in that said conveyor (6) comprises a roller (7)   rotated about its axis and carrying said articles   keys (5) uniformly distributed along its periphery, said laser block (56) functioning to perforate each of said articles (5) while the latter is on a piercing arc (AB) subtended by an angle to center lower than 3600, said actuator (28) performing a complete rotation during the time set by said associated articles (5) to traverse said piercing arc (AB). 3 Process according to claim 2, characterized in that said laser block (56) comprises at least one pulsating generator of at least one laser beam (55),   and at least one reflector (57, 58) for selectively directing   beam (55) on a portion (4) to be pierced from each of said articles (5), said reflector (57, 58) being   rotatably mounted about the axis of said roller (7) and   causing it to perform a complete rotation about said axis during the time set by said roller (7)   to advance each of those articles (5) by at least one cement (P).   4 Process according to one of claims 1 to   3, characterized in that said perforations (3) are formed in each of said articles (5) while the article (5) traverses a piercing arc (AB) having an equal length   to that said spacing (P) multiplied by the number of people   forages (3) to be formed in each of said crowns (2) on each of those articles (5).   Method according to one of claims 1 to   3, characterized in that said perforations (3) formed in each of said articles (5) are formed while the article (5) traverses a piercing arc (AB) having a length equal to that of said spacing gap ( P) multiplied by a multiple of the number of perforations (3) to be formed in each ring (2) on each of said articles (5). 6 Device for forming perforations in   bar-shaped articles, in particular cigarets   characterized by the fact that it comprises: a conveyor (6) for driving said articles (5) in displacement transversely with respect to their long axis of a predetermined advance path, said   conveyor (6) being able to support said articles-   (5) spaced from each other with constant spacing (P),   a retaining device (29) for   pler each of said articles (5) to said conveyor (6) along at least a portion of said path, said retainer (29) comprising, for each of said articles (5), an actuator (28) movable with said conveyor   (6) and rotated about its axis to communicate with   the associated Article (5), simultaneously with the said trans-   lation along said path, a rotation about its axis, and at least one laser generator block (56) functioning to form, on each of said articles (5), at least one ring (2) perforations (3) during said rotation of the associated article (5) around its axis.   Apparatus according to claim 6, characterized in that said conveyor (6) comprises a roller (7) rotatably mounted about its axis and intended to support said articles (5) in a uniformly spaced manner along its periphery, said laser block (56) operable to act on each of said articles (5) while the latter is traversing a piercing arc (AB) subtended by an apex angle of less than 3600, and said piercing member   maneuver (28) operating in a manner   on itself during the time set by the   associated key (5) to traverse said piercing arc (AB).   8 Device according to claim 7, characterized   characterized in that said laser block (56) comprises a generator generating pulses of at least one beam (55) of laser beams, and a reflector (57, 58) for selectively directing said beam (55) over a portion   (4) to pierce each of said articles (5), said reflection   said rotator (57,58) being rotatably mounted about the axis of said roller (7), an actuator (53) for rotating said reflector (57,58) so that it rotates complete about said axis in the time set by said roller (7) to advance each of said articles (5) by at least one spacing interval (p).   9 Device according to one of claims 7   and 8, characterized in that said piercing arc (AB) has a length equal to that of one of said spacing intervals (P) multiplied by the number of perforations (3) to be formed in each of said rings (2 ) on each of said articles (5).   Device according to one of the claims   7 and 8, characterized by the fact that said piercing arc (AB) has a length equal to that of one of said spacing intervals (P) multiplied by a multiple of the number of perforations (3) to be formed in each of said crowns   (2) on each of the said articles (5).   11 Device according to one of the claims   6 to 10, characterized in that said operating member (28) comprises, for each of said articles (5), at least one sleeve (38) coaxial with the article (5) and intended to receive a respective end thereof last, additional actuators (13,40) etan L coupled to each of said sleeves (38) to drive it in rotation around of its own axis.   Apparatus according to claim 11, characterized   characterized in that said conveyor (6) comprises a roller   water (7) provided with a central shaft (12) rotatably mounted   around its axis, said additional actuating means   res (13,40) comprising, for each of said sleeves (38), a gear train (40) of which a first output gear (41) is keyed to said shaft (12) and a second output gear (39) ) is keyed on a shaft (37) rigidly connected   to the sleeve (38) and coaxial with the latter.   13 Device according to one of the claims   11 and 12, characterized by the fact that said additional actuators (13, 40) furthermore comprise, for each of said sleeves (38), a slide (27) sliding   parallel to the axis of the associated article (5).   singing and away from the associated end thereof, under the control of a cam (34) for holding each sleeve (38) mounted in position on the associated end of the associated article (5), for all the time during which this   the last is subjected to the action of said laser block (56).